Folding machine having at least one pair of knife shafts

ABSTRACT

The folding machine includes at least one pair of knife shafts, the knife shafts ( 22, 24 ) of which are, in a working position, mounted parallel to each other between two spaced-apart side walls ( 18, 20 ) of the folding machine ( 10 ). In order, in parallel with the production process, to be able to prepare knife shafts for a subsequent production process, the knife shafts ( 22, 24 ) are mounted in a cassette ( 28 ) which can be displaced through a sidewall ( 20 ) facing the operator from an inserted position, in which the knife shafts ( 22, 24 ) are in their working position, into a pull-out position, in which the knife shafts ( 22, 24 ) are outside the folding machine ( 10 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a folding machine having at least one pair ofknife shafts, the knife shafts of which are, in a working position,mounted parallel to each other between two spaced-apart side walls ofthe folding machine.

2. Description of the Background Art

In order to be able to cut, cut out, perforate, crimp etc. folded papersheets perpendicular to a fold, i.e. in the running direction of thesheets, pairs of knife shafts are provided upstream and downstream ofthe folding rollers of a folding unit. These generally concern pairs ofknife shafts in which one knife shaft is fitted with upper knife toolsand the other knife shaft is fitted with lower knife tools, said toolsbeing arranged on a tool holder fitted on the knife shaft. The knifeshafts are fitted with appropriate tools depending on the requirementsof the task. A corresponding folding machine is disclosed, for example,in DE 30 25 239 C2. In the case of the known folding machines, the knifeshafts are usually mounted on the side walls of the folding machine. Forthis reason, they can be removed only if the folding machine is at astandstill. For this purpose, it is generally necessary first of all topull out the buckle plates. After their fastening has been released, theknife shafts then have to be lifted out over the side walls of themachine. Since the knife shafts are generally very heavy, this work isvery laborious. Finally, the knife shafts can only be set in a precisemanner when they are installed in the folding machine. For this purpose,auxiliary means are fitted in the direct vicinity of the knife shafts.These are, for example, rulers having a tape measure printed on themenabling the position of the tool to be read.

SUMMARY OF THE INVENTION

The invention is based on the object of providing, with structurallysimple means, a folding machine in which rapid changing of the knifeshafts is possible in a simple manner.

This object is achieved by a folding machine comprising at least onepair of knife shafts which are, in a working position, mounted parallelto each other between two spaced-apart side walls of said foldingmachine, wherein said knife shafts are mounted in a cassette which isdisplaceable through a sidewall facing an operator from an insertedposition, in which said knife shafts are in an working position thereof,into a pull-out position, in which said knife shafts are located outsidesaid folding machine.

Since the knife shafts are mounted in the cassette which can bedisplaced through the sidewall from the inserted position into thepull-out position, changing of the knife shafts is possible withoutremoval of the buckle plates of a folding unit connected upstream. Inaddition, it is possible to preset a pair of knife shafts while thefolding machine is running, as a result of which the set-up time can besubstantially reduced.

The cassette is preferably arranged in a drawer which can be insertedand pulled out through the side wall. When the drawer is pulled out, thecassette can be removed and a new cassette placed into the drawer. Afterthe drawer has been inserted, the changing of the pair of knife shaftsis complete.

In one particular embodiment, the cassette has an end wall facing thedrive and an end wall facing the operator, said walls being spaced apartand being connected to each other by a crosspiece. The knife shafts aremounted on the end by bearing devices.

The bearing devices of at least one knife shaft can preferably beadjusted in order to set the nip between the knife shafts. Thisadjusting device is part of the knife shaft cassette. The adjustment maytake place outside the folding machine.

For a rapid connection to the drive facing the folding machine, thebearing devices facing the drive can be mounted rotatably in the endwall facing the drive, and pass through said end wall.

In order to center the cassette, it is advantageous if a respectivefixing pin is fitted on the two end walls and, in the inserted position,engages in a centering opening in the respective side wall of thefolding machine.

A precise setting of knife holders on the knife shafts can be achievedby the fact that a scale is provided on the knife shaft, said scalepreferably being engraved in it.

Since the setting of the knife holders on the knife shafts can takeplace outside the machine, the operator can stand directly in front ofthe knife shaft cassette during the tool change, so that parallax errorsdo not occur.

BRIEF DESCRIPTION OF THE INVENTION

An exemplary embodiment of the invention will be explained in greaterdetail below with reference to drawings, in which:

FIG. 1 shows a folding machine with a pulled-out cassette,

FIG. 2 shows the folding machine of FIG. 1 with an inserted cassette,

FIG. 3 shows a cassette in which a pair of knife shafts is fitted,

FIG. 4 shows the section IV—IV of FIG. 3,

FIG. 5 shows a perspective view of the cassette,

FIG. 6 shows a knife shaft on which a scale is provided,

FIG. 7 shows the scale of the knife shaft in FIG. 6 on an enlargedscale,

FIG. 8 shows the view of FIG. 4 on an enlarged scale,

FIG. 9 shows a left side view of the cassette of FIG. 3 on an enlargedscale.

DETAILED DESCRIPTION OF THE INVENTION

The folding machine 10 shown in FIGS. 1 and 2 has a buckle-plate foldingunit having a buckle plate 12, downstream of which, in the runningdirection of the sheets, are arranged folding rollers 14, 16 which aremounted in a sidewall 18 facing the drive and a sidewall 20 facing theoperator. As can be seen in FIG. 2, a pair of knife shafts comprising anupper knife shaft 22 and a lower knife shaft 24 is arranged downstreamof the folding rollers 14, 16 in the running direction of the sheets.Five knife holders 26 are arranged at equal spacing, as seen in thelongitudinal direction, on the knife shafts 22, 24 and on them tools(not shown) for cutting, cutting out, perforating, crimping etc. a sheetleaving the buckle plate 12 are arranged. The knife shafts 22, 24 aremounted in a cassette 28, the design of which will be explained ingreater detail below. The cassette 28 itself is arranged on a drawer 30which can be pulled out of the folding machine 10 through an opening inthe sidewall 20 facing the operator until the entire cassette 28 isoutside the folding machine 10. This position is shown in FIG. 1.

FIG. 2 shows the position of the drawer 30 in which it is insertedcompletely into the folding machine 10. In this case, the drawer 30bears with its end wall 34 facing the drive against the sidewall 18facing the drive. The drawer 30 extends completely between the two sidewalls 18, 20. The drawer 30 rests on a horizontal base 32 which extendsbetween the side walls 18, 20. To guide the movement of the drawer 30from the inserted position into the pulled-out position, guide means(not shown) are provided which guide the drawer 30 in such a manner thatit executes a rectilinear movement. As such a guide for a drawer 30, usecan be made, for example, of two three-part telescopic guides which areconnected to one another by a drawer base and, in the inserted state,are arranged completely between the machine side walls. The cassette 28is inserted loosely into the drawer 30.

The cassette 28 with the knife shafts 22, 24 arranged parallel to eachother on it is shown in greater detail in FIGS. 3 to 5, 8 and 9. Thecassette 28 has an end wall 34 facing the drive and an end wall 36facing the operator, said end walls being connected to each other bycrosspieces 38, 40. The two knife shafts 22, 24 are mounted rotatably,for example via plug-in spindles or half-shells, in knife shaftmountings 42, 44 on the operator side. The upper mounting 42 can bedisplaced in a plane defined by the two shaft axes or is designed suchthat it can be rotated about an eccentric point in order to make itpossible to set the nip between the two knife shafts 22, 24.

As can be seen in FIGS. 8 and 9, the knife shafts 22, 24 are mountedrotatably on the drive side by bearing devices 46, 48, the bearingdevices 46, 48 being designed simultaneously as a rotary leadthrough andcoupling element which are connected in a rotationally fixed manner to adrive element of the folding machine when the cassette 28 is insertedinto the folding machine 10. The upper bearing device 46 can bedisplaced in the plane defined by the two shaft axes while the lowerbearing device 48 is arranged in a fixed manner.

The upper bearing device 46 has a bearing shell 60 in which a ballbearing 64 through which the shaft 22 passes is arranged. The bearingshell is guided along a straight line, which passes through the centeraxes of the shafts 22, 24, through two guide blocks 68, 70 arranged onboth sides. One end of a threaded pin 73 engages in the upper side ofthe bearing shell 60. The other end is in engagement with a threadedopening which is formed in a threaded block 72 which is fastened to thesidewall 34 adjacent to the upper edge thereof. The threaded pin 73 isaccessible from above via an opening in the threaded block 72, and canbe rotated by means of a suitable tool in order to set the nip betweenthe two knife shafts 22, 24.

The lower bearing device 48 has a bearing block 62 which is fastened tothe sidewall 34 and in which a ball bearing 66 through which the shaft24 passes is arranged.

As can be seen in FIG. 9, coupling sections 74, 76 are provided at thatend of the knife shafts which faces the drive, said coupling sectionsbeing used to connect the knife shafts to drive elements on the foldingmachine 10 when the cassette 28 is in the position shown in FIG. 2, thecoupling sections 76, 78 being designed in such a manner that an axialor radial offset is compensated for and the torque is introduced in apositive-locking manner.

Above the upper knife shaft 22, a fixing pin 50 which protrudes towardthe end wall 34 facing the drive is provided on the end wall 36 facingthe operator. In the inserted position of the cassette 28 which is shownin FIG. 2, this fixing pin 50 engages in a centering opening in theoutside of the sidewall 20. As can also be seen in FIG. 2, the end wall36 facing the operator rests with its edge on the sidewall 20. A furtherfixing pin 51 extends outward from the end wall 34 facing the drive. Inthe inserted position of the cassette 28 shown in FIG. 2, this fixingpin 51 engages in a centering opening in the inside of the sidewall 18,as a result of which the cassette is automatically aligned.

The tool holders 26 are fitted releasably on the shaft body 23 of theknife shafts 22, 24. Precise positioning of the tool holders 26 on theknife shafts 22, 24 is made possible by a scale, as is shown in FIGS. 6and 7. A vernier is engraved into the surface of the shaft body 23 ofthe knife shafts 22, 24 in the longitudinal direction of the knifeshafts 22, 24 as the scale 52. Owing to the precise scale 52 directly onthe knife shaft 22, 24, it is possible to fasten a tool holder 26 on theknife shaft 22, 24 in a precise manner. The fastening accuracy isadditionally increased by the fact that it is possible for an operatorto fasten the tool holders 26 to the knife shafts 22, 24 outside thefolding machine 10. This avoids parallax errors.

1. A folding machine comprising at least one pair of knife shafts whichare, in a working position, mounted parallel to each other between twospaced-apart side walls of said folding machine, wherein said knifeshafts are mounted in a cassette which is displaceable through asidewall facing an operator from an inserted position, in which saidknife shafts are in an working position thereof, into a pull-outposition, in which said knife shafts are located outside said foldingmachine wherein said cassette comprises a first end wall facing saiddrive and a second end wall facing said operator, said first and secondend walls being spaced apart and being connected to each other by atleast one crosspiece, wherein said knife shafts are mounted on saidfirst and second end walls by means of bearing devices and wherein saidbearing devices facing said drive are mounted rotatably in said end wallfacing said drive, pass through said end wall and can be connected to adrive.
 2. A folding machine as claimed in claim 1, wherein said cassetteis arranged in a drawer which can be inserted and pulled out throughsaid sidewall facing said operator.
 3. The folding machine as claimed inclaim 1, wherein said bearing devices of at least one of said knifeshafts can be adjusted in order to set a nip between said knife shafts.4. The folding machine as claimed in claims 1, wherein a respectiveprotruding fixing pin is fitted on said end walls and, in said insertedposition, engages in a centering opening in a corresponding one of saidsidewalls of said folding machine.
 5. The folding machine as claimed inclaim 1, wherein tool holders are fastened releasably on said knifeshafts and a scale extending in a longitudinal direction of said knifeshafts is provided on said knife shafts.
 6. The folding machine asclaimed in claim 5, wherein said scale is engraved in said knife shafts.